Limiting the fuel supply to an internal combustion engine



Aug. 2, 1966 LIMITING THE FUEL SUPPLY To AN INTERNAL COMBUSTION ENGINE Filed March 2, 1.964

- 2 5 a 9 a 9 $75 a FUEL LIMITING ABUTMENT STRUCTURE .36 SPEED 51 RESPONSIVE CONTROL 39 DEVICE 47 INTAKE AIR TEMPERATURE RssPous/vE 12 CONTROL DEVICE BAROMETRIC PRESSURE RESPONSIVE 13 CONTROL DEV/CE ELECTRIC POWER SUPPLY W. BARTH ETAL 2 Sheets-Sheet 1 I ENGINE GOVEQNOR FIG.2

INVENTORS WHLTER BARTH 66mm JAHN [Ru/N 032-21? Aug. 2, 1966 w. EARTH .--=ET AL 3,263,662

LIMITING THE FUEL SUPPLY TO AN INTERNAL COMBUSTION ENGINE Filed March 2, L96 2 Sheets-Sheet 2 A F 6. 4 ;-126 M B A 725 I max max MW 51 I FIG. 3

B2 A2 56 83 83 11 4 a 52 #54 Q! m 5 B1. 63 O F 64 -a X ""61 v V A 62 A 58 -53 m. n max F 55 ENGINE ROTATIONAL SPEED INVENTORS Warm EARTH Gfilvrm :ZIH/Y [RWl/V 0.5 7161? Al FONS /7A GMA/V/V United States Patent "ice 3,263,662 LIMITING THE FUEL SUPPLY TO AN INTERNAL COMBUSTION ENGINE Walter Barth, Tettnang, Wurttemberg, Giinter Jahn, Friedrichshafen, Erwin Oster, Immenstaad (Bodensee), and Alfons Hagmann, Friedrichshafen, Germany, assignors to Maybach-Motorenbau G.m.b.H., Friedrichshafen, Germany, a firm of Germany Filed Mar. 2, 1964, Ser. No. 348,328 Claims priority, application Germany, Mar. 9, 1963, M 56,058 14 Claims. (Cl. 123-440) The present invention relates to a system for limiting the fuel supply to an internal combustion engine.

It is known to limit the fuel supply to an internal combustion engine, for example, by providing an abutment defining the extent of movement of a fuel supply regulating element and changing the position of the abutment in accordance with a predetermined torque curve. The position of the abutment may be changed by means of a centrifugal type governor driven by the engine. In this way the engine can be operated within a smokeless range or it can be avoided that a permissible torque is exceeded. The invention is concerned with such limitation of the fuel supply to an internal combustion engine.

If the internal combustion engine, for example a diesel engine, drives a rail vehicle through a hydrodynamic torque converter, for example of the type known as Fdttinger converter, the conventional engine governor of the. diesel engine adjusts the fuel supply according to the power absorbed by or input torque of the torque converter. If there is an oxygen deficiency, as may be the case if the vehicle passes through a narrow tunnel, particularly a one-track tunnel, the governor tends to counteract the loss of power caused by the oxygen deficiency, by increasing the rate of fuel supply. Because of the oxygen deficiency the additional fuel cannot be burned. Besides the increased fuel consumption, such operation entails coking of the cylinder head and of the valves. This is avoided by the system according to the invention whereby the movement of an element controlling the fuel supply is limited by an abutment whose position is changed so that the maximal possible engine torque at any rotational speed above the idling speed exceeds the input torque absorbed by the torque converter operating at said speed,.by a small amount necessary for a predetermined acceleration of the vehicle. In one embodiment of the invention this is accomplished by using a centrifugal type speed-controlled regulator for displacing a piston valve provided with control fluid feedback means operable to control the flow of a control fluid in such a manner that with an increasing speed, control fluid is admitted to a cylinder containing a spring-loaded piston which is operatively connected to the abutment while control fluid is released from the cylinder with a decreasing speed, until equilibrium prevails at the control valve.

According to a further feature of the present invention, the limitation of the rate of fuel supply is additionally made responsive in an advantageous manner to the temperature of the air supplied to the engine. To accomplish this an element expanding at increasing temperature may be placed in the intake air supply conduit of the engine and connected to a control valve associated with 3,263,662 Patented August 2, 1966 a follow-up piston for increasing, at dropping temperature, the pressure of the control fluid admitted to the piston valve actuated by the centrifugal type speed-controlled regulator and for decreasing said pressure at rising air temperature.

This temperature responsivecontrol of the abutment means for limiting the fuel supply to the internal combustion engine may be so devised that the effect of a temperature change of the intake air is relatively little as long as the intake air temperature is below a predetermined temperature and is relatively great at an equal temperature change above said predetermined temperature. In order to produce this kind of control a twoarm lever may be interposed between the temperature responsive means and the valve means and two spaced fulcrums may be provided for this lever, one fulcrum being operative when the intake air temperature is below the predetermined temperature for effecting a relatively small movement of the valve means at a predetermined temperature change, and the second fulcrum being operative when the combustion air temperature is above the predetermined temperature for effecting a relatively great movement of said valve means at equal temperature changes above said predetermined temperature.

The limitation of the fuel supply may be made additionally responsive to the pressure of the ambient air, for example, by operatively connecting the valve means actuated by the air temperature to bellows which are responsive to air pressure.

The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, and additional objects and advantages thereof will best be understood from the following description of embodiments thereof when read in connection with the accompanying drawing wherein:

FIG. 1 is a schematic illustration of the power plant of a diesel locomotive which may be provided with means for limiting the fuel supply according to the invention.

FIG. 2 is a schematic, part-sectional illustration of an apparatus for limiting the fuel supply according to the invention.

FIG. 3 is a diagrammatic, longitudinal sectional illustation of a modified device for making the limitation of the fuel supply dependent on the temperature of the ambient air, and

FIGURE 4 is a diagram illustrating the relationship of produced engine torque to engine rotational speed.

Referring more particularly to FIG. 1 of the drawing, numeral 1 designates a diesel locomotive, numeral 2 designates a diesel engine provided with a conventional engine governor 16 and a fuel supply limiting apparatus 10 according to the invention. The engine torque is transmitted by a universal-joint shaft 3 to a Fiittinger torque converter 4. The converted torque is transmitted through articulated shafts 5, distributor gears 6, shafts 7 and axle drives 8 to wheel sets 9.

FIG. 2 is a detailed illustration of an example of the apparatus 10. The apparatus comprises a device 11 responsive to the speed of the diesel engine, a device 12 responsive to the temperature of the intake air, a device 13 responsive to barometric air pressure, and means M actuated by said devices for limiting the movement of a control rod 15 of the engine govern-or 16 and for thereby limiting the rate of fuel supply adjusted by the engine governor 16. The apparatus also includes a testing device #17.

The engine governor 16 is a conventional apparatus comprising a centrifugal type governor maintaining a predetermined speed by adjusting the fuel suply in proportion to the load. The engine governor 16 is driven by a shaft 161 operatively connected to and driven by the engine output shaft, not shown, which is normally connected with the engine crankshaft. Conventional weights 162 press by means of a suitable conventional mechanism against a spring 163 whose tension can be adjusted by an adjusting screw .164. A conventional governor sleeve 166 actuates a lever 165 to the free end of which is connected the control rod 15. The governor device 16 forms no part of the present invention, and other conventional governors maybe used. However, the upward movement of the rod and therewith the specific maximum fuel supply is limited in every case by the abutment 87.

A control fluid, for example oil, is pumped by a pump 18 from a container 19 through a pipe 20 into the device 12 wherein the pressure of the fluid is changed in response to the temperature of the air supplied to the diesel engine. The fluid passes as an already once controlled pressure through a pipe 21 into the device 11 which controls the flow of fluid into a pipe 22 into the fuel supply limiting means 14 in response to the engine speed.

A pipe 23 connects the pipe 20 to the device 13 which is connected by a pipe 24 to the device 12.

A pipe 25 connects the pipe 20 to the testing device 17.

Numeral 26 designates a return pipe for returning control fluid from the device 11 to the container 19. Control fluid is returned from the devices 17, 12 and 13 to the pipe 26 through pipes 27, 28 and 29, respectively.

The control device 11 includes a centrifugal speed-controlled regulator 30 actuating a piston valve 32 in a housing 31. The speed-controlled regulator 30 comprises carriers 3-3 rotated by a control shaft 34 of the diesel engine, i.e., rotated at the rotational speed of the diesel engine or proportional thereto. The carriers 33 swingably support angle levers 36 provided with flyweights and acting on a collar 37 on a rod 38 which is connected to the piston valve 32. An extension 39 of the rod 38 is axially movable in a recess 40 of the control shaft 34 and is connected thereto for rotation therewith. Therefore, the piston valve 32 continuously rotates in the cylinder 41 formed in the housing 31 whereby static friction is avoided and very little force is needed for axially moving the valve. A circumferential recess 42 on the valve 32 affords a valved connection of the pipes 21 and 22. A channel 43 is provided in the housing 31 for connecting the pipe 22 with a chamber 44 in the cylinder 41 at the side of the valve 32 which is distant from the rod 38. The valve assembly 32 forms in effect a first valve controlling the flow of pres sure fluid from a supply conduit 21 to a discharge conduit 22, and a second valve controlling the flow of pressure fluid from the channel or conduit 43 to the return pipe 26.

The control device 12 comprises an element 45 placed in an intake air supply pipe 46 of the diesel engine. The element 45 expands at increasing air temperature and contracts at decreasing air temperature. The movements of the element 45 are transmitted by means of a pin 47 to a cylinder 48 and a piston 49 axially movable in the cylinder 48. A control valve 52 is pressed by a spring 51 against a piston rod connected to the piston 49. The valve 52 is surrounded by a hollow follow-up piston 53 and a sleeve 54 extending therefrom. The piston 53 is axially movable in a cylinder 55 and the sleeve 54 is axially movable in a cylinder 56 formed in a valve housing 57. The follow up piston 53 divides the cylinder 55 to form chambers 58 and 59 on both sides of the piston 53. A compression spring 60 is placed in the chamber 59 for pressing the piston 53 to the right. The sleeve 54 extending from the piston 53 is provided with apertures or ports 61 and 62. The valve 52 has an annular recess 63. The pipe 20 terminates in an annular groove 64 in the housing 57, surrounding the sleeve 54. The chamber 58 is connected to the pipe 2 1 and the cylinder 55 is connected to the return pipe 28. A flexible pipe 65 connects the pipe 24 to the interior of the cylinder 48.

The control device 13 includes an aneroid barometer 66, a pilot valve 67 movable in a cylinder formed by a housing 68, and a source of electric current 69 connected by wires or lines 70, 71 to a solenoid coil 72. A switch comprising contacts 73 opposite a contact plate 74 connected to the barometer 66 is interposed in the line 71. The valve 67 has an annular recess 76 formed between two spools and a stem 77 extending through an end wall 78 of the cylinder 75. The outer end of the stem 77 forms an armature 79 inside of the coil 72. A compression spring 80 is placed inside the cylinder 75 and rests with one end against the wall 78. The second end of the spring 80 presses against the valve 67.

The control device 14 comprises a servo-piston 83 movable in a cylinder '81 and urged toward the lower end of the cylinder by means of a spring 82. A rod 84 connected to the upper side of the piston 83 has a free end pivotally connected to a lever 85 swingable on a fulcrum mounted on a casing 86 wherein the cylinder '81 is formed. The free end of the lever 85 forms an abutment 87 which is opposite an abutment 88 formedon the control rod 15. The latter is provided with a rack 89 cooperating with a toothed segment 90 which is rigidly connected to an actuating shaft 91 of a fuel injection device, not shown. A pointer 92 connected to the shaft 91 indicates on a scale 93 the rate of flow of fuel to the diesel engine.

The testing device 17 comprises cylinders 95 and 96 formed in a housing 94. A piston valve 97 having an annular recess 98 is axially movable in the cylinder 95. The valve 97 can be moved against the action of a spring 100 into testing position by pressing a button 99. The cylinder 96 is coaxial of the cylinder 41 of the control device 11 and contains a piston 102 urged to the left by a spring 101. A rod 103 connected to the piston 102 extends into the chamber 44 where it carries a socket 104 one end of which forms a spring cap 105. The socket 104 is provided with a slot 106 longitudinally of the socket and receiving a transverse pin 107 mounted on the rod 103. This affords a limited axial movement of the socket 104 relative to the piston rod 103. A spring 108 is placed between the cap and the right end wall of the chamber 44 and urges the socket 104 to the left, as seen in FIG. 2.

Operation of the apparatus:

At constant speed of the engine the control device 11 is in a state of equilibrium since shaft 34 is driven by the engine shaft. Under equilibrium conditions, the force produced by the flyweights 35 and transmitted through the levers 36, the collar 37, and the rod 38 to the piston valve 32 is equal to the force exerted by the pressure fluid in the chamber 44 on the end face of the piston valve 32. In the equilibrium position shown in FIG. 2 the piston valve 32 closes the passage from the pressure fluid supply conduit 21 to the conduit 22 so that the fluid pressure acting on the piston 83 is not changed and the piston 83 remains in a position corresponding to said pressure. The piston 83 places the abutment 87 by way of the rod 84 and the lever 85 into a position corresponding to the engine speed at this time and limits the maximum fuel supply which can be effected by the engine governor 16. Since the chamber 44 is connected by the conduit or channel 43 to the pipe 22 and the return pipe 26 is blocked by the piston valve 32 the pressure in the system 22, 43, 44 remains constant.

Increasing speed of the engine causes an increase in the speed of the shaft 34 and therewith outward movement of the flyweights 35 whereby the collar 37 and the piston valve 32 are moved to the right into the cylinder 41 so that the inlet of pipe 22 is opened and connected for fluid flow to the pipe 21. This causes an increase of the pressure acting on the servo-piston 83 and movement thereof against the action of the spring 82. The increased pressure acts also in the chamber 44 and moves the piston valve 32 to the left against the force exerted by the flyweights until a state of equilibrium is obtained whereby the valve 32 closes the inlet of pipe 22. A new constant pressure now prevails in the pipe 22, the conduit 43, the chamber 44 and in the cylinder 81, and the lever 85 and the abutment 87 are held in the new position permitting a greater maximum fuel rate and corresponding to the new (increased) engine speed.

Decreasing speed of the internal combustion engine causes the shaft 34 to decrease in its rotational speed and therewith a decrease of the force exerted by the flywei-ghts 35 so that the pressure in the chamber 44 can move the piston valve 32, the rod 38 and the collar 37 to the left, causing inward movement of the flyweights 35. Movement of the valve 32 to the left opens the inlet of the fluid return pipe 26 so that pressure fluid is released and the pressure in the chamber 44, in the conduits 43 and 22 and in the cylinder 81 is reduced. The spring 82 can now move the servo-piston 83 downward for swinging the lever 85 in clockwise direction and placing the abutment 87 in a new position whereby less maximum fuel supply is allowed, corresponding to the new (decreased) speed of the engine. Due to the reduced pressure acting on the end face of the valve 32 the flyweights 35 can cause movement of the valve 32 to the right for closing the inlet of the return pipe 26. The system is now once more in balanced condition.

As explained hereinabove, the control device 11 reduces or increases the fluid pressure in the pipe 22, in the conduit 43, in the chamber 44 and in the cylinder 81 in dependence on the speed of the diesel engine. Apredeterm-ined pressure corresponds to each engine speed and, in turn, a predetermined position of the abutment 87 for limiting the movement of the control rod 15 corresponds to each predetermined pressure. The fluid pressure in the system 22, 43, 44, 81 is proportional substantially to, i.e., increases substantially as the square of the engine speed, the maximum pressure in the system being equal to the maximum pressure fluid in the supply pipe 21. According to the invention the pressure in the supply pipe 21 is changed by the control device 12 which is responsive to the temperature of the intake air admitted to the internal combustion engine so that the pressure in the cylinder 81 is reduced and fuel supply additionally limited when the temperature of the combustion air increases, and conversely as will be described more fully hereinafter.

If the temperature rises in the pipe 46 which conducts intake air to the diesel engine, to produce the necessary additional fuel supply limitation by reducing the pressure in cylinder 81, the element expands and moves by means of a pin 47 the hollow cylinder 48 which normally does not contain pressure fluid. The piston 49 is therefore all the way inside the cylinder 48 and its end face abuts against the left end wall of the cylinder 48. Movement of the cylinder 48 by the temperature sensitive element 45 is transmitted through the piston 49 and the piston rod 50 connected thereto to the valve member 52 against the action of the spring 51. The aforedescribed movement of the valve member 52 opens an aperture 62 in the sleeve 54 connected to the follow-up piston 53 so that pressure fluid can flow from the chamber 58 into the chamber 59 wherefrom the pressure fluid is released through the. return pipe 28. The pressure at the right side of the follow-up piston 53 drops and the spring 60 presses the piston 53 with its sleeve 54 to the right whereby the aperture 62 is closed again by the valve member 52. Decreasing pressure in the chamber 58 causes a decrease of the pressure in the pipe 21 which pressure is the maximal possible pressure which may prevail in the pipe 22 and in the cylinder 81 of the device 14. Increasing intake air temperature thus decreases the maximal adjustable fuel supply by the engine governor 16. Drop of the in- 6 take air temperature causes contraction of the element 45. The cylinder 48, the piston 49 and the valve member 52 follow the pin 47 because of the action of the spring 51. This causes opening of the aperture 62 in the sleeve 54 so that pressure fluid can flow from the supply pipe 20, the annular recess 64 in the casing 57, the annular recess 63 in the valve member 52 and the aperture 62 into the chamber 58 for pressing the follow-up piston 53 to the left against the pressure of the spring until the aperture 62 is again closed. The pressure in the chamber 58 rises and, consequently, there is an increase of pressure in the pipes 21 and 22 and in the cylinder 81. The abutment 87 is moved upward and the maximal fuel supply to the combustion engine by the enginegovernor 16 is allowed to increase.

The switch plate 74 connected to the aneroid barometer 66 of the device 13 is normally spaced from the contacts 73. If the pressure of the ambient air decreases, for example, if the rail vehicle driven by the diesel engine moves up a mountain, the element 66 expands and, at a predetermined pressure, the plate 74 abuts against the contacts 73 and closes the electric circuit including the solenoid 72. This causes movement of the pilot valve 67 to the left against the action of the spring 80. The pressure fluid supply pipe 23 is connected through the annular recess 76 of the valve 67, through the pipe 24 and the flexible conduit to the interior of the hollow cylinder 48. The pressure fluid tends to press the piston 49 out of the cylinder 48 until the piston reaches an abutment provided in the cylinder 48. This: movement of the piston 49 is transmitted through the piston rod 50 to the valve member 52 so that the aperture 62 is opened and the effect is the same as the aforedescribed eifect caused by increasing intake air temperature. Pressure fluid passes from the chamber 58 at the right side of the piston 53 to the left side of the piston 53 and is released through the pipe 28. The pressure in the space 58 drops and the spring 60 pushes the follow up piston 53 with its sleeve 54 relative to the valve member 52 for closing the apera ture 62. Decreasing pressure in the space 58 is accompanied by a corresponding decrease of the pressure of the pressure fluid in the pipe 21 so that the pressure in the pipe 21 which was decreased by the rising air temperature in the pipe 46 is further decreased when the atmospheric air pressure drops below a predetermined pressure. The maximal rate of supply of fuel to the engine allowed by the abutment 87 is therefore still further reduced.

In the illustrated example the air pressure stepwisely actuates the valve member 52. If desired, a more continuous actuation may be effected by arranging a plurality of air pressure responsive devices in series relation. The effect of the air temperature on the setting of the abutment 37 may be eliminated by omitting the temperature responsive device 45 so that the valve 52 is positioned solely in response to the air pressure. In lieu of intake air temperature other operating characteristics, for example cooling water temperature, or other combinations of operating characteristics may be used for influencing the engine speed responsive device 11.

The device 17 affords testing of the system. During normal operation pressure fluid flows through the pipe 25, the annular recess 98 of the piston valve 97 in the cylinder and through the conduit 110 into the cylinder 96 and pushes the piston 102 to the right against the action of the springs 101 and 108. The socket 104 which is connected to the piston rod 103 extending from the piston 102 is thereby pulled into its right end position so that in no position of the piston valve 32 will the spring cap 105 forming part of the socket 104 be abutted by the end face of the piston valve 32. If the push button 99 is pressed against the action of the spring 100 into its left end position, the conduit is separated from the pipe 25 by the piston valve 97 and is connected to the pressure fluid return pipe 27 so that the pressure drops in the conduit 110 and in the cylinder 96. The spring 101 can now push the piston 102 into its left end position. The spring 108 moves the spring cap 105 to the left until it abuts against the end face of the piston valve 32 and pushes the latter to the left against the action of the flyweights 35. The pressure fluid return pipe 26 is now con nected to the chamber 44 and the pressure drops in said chamber and in the conduit 43, the pipe 22 and in the cylinder 81. The piston valve 32, therefore, returns into equilibrium position whereby the inlet of the return pipe 26 is closed. Due to the reduced pressure the piston 83 moves downward and swings the lever 85 in clockwise direction for downward movement of the abutment 87. If the engine speed responsive control device 11 operates correctly, the change in position of the abutment 86 resulting therefrom amounts to a predetermined value at any operating speed of the internal combustion engine.

FIG. 3 shows a temperature responsive device for limiting the fuel supply to an internal combustion engine which device is similar to that shown in FIG. 2 and designated by numeral 12. Like elements shown in FIGS. 2 and 3 are designated by like numerals. The device shown in FIG. 3 differs from that shown in FIG. 2 by the provision of a two-arm lever 111 and push rods 112 and 113 between the pin 47 of the temperature sensitive element 45 and the cylinder 48. The lengths of the push rods 112 and 113 can be adjusted by manipulating nuts 114 and 115, respectively, so that the mechanism can be adjusted to operate without lost motions. Two spaced bearing surfaces 122 and 123 are provided inside of a casing 124 for supporting the lever 111 having the arms 116 and 117 either on a protuberance 120 cooperating with the surface 122, or on a protuberance 121 cooperating with the surface 123. The valve means 52 isprovided with an indicator 125 which indicates on a scale 126 the pressure of the pressure fluid in the pipe 21 connecting the devices 11 and 12.

In the low temperature range wherein the element 45 is little expanded the protuberance 120 of the lever arm 117 sits on the surface 122 to form a fulcrum. The lever 111 is held on this fulcrum by the rod 113 which is pressed downward by the spring 51 through the valve element 52, the piston rod 50, the piston 49 and the cylinder 48. The element 45 expands at rising temperature and turns the lever 111 through the pin 47 and the rod 112 clockwise on the surface 122 until the protuberance 121 comes to rest on the surface 123 whereby the protuberance 120 is lifted from the surface 122. This change-over from the fulcrum 120, 122 to the fulcrum 121, 123 takes place at a predetermined temperature of the engine air, for example 65 C. Due to this change of position of the fulcrum of the lever 111 the rod 113 travels farther at equal movement of the rod 112 in the high temperature range than at temperatures below the predetermined temperature. This causes a greater drop of the pressure of the pressure fluid at temperature increases above the predetermined temperature than at equal increases below the predetermined temperature. The result is an increased effect of the system according to the invention and increased safety of operation of the internal combustion engine.

In summary, the present invention provides a control system which limits the maximum rate of flow of fuel supplied to the engine cylinder in such a manner that the maximum engine torque permitted by abutment 87 at any given engine rotational speeds exceeds the input torque of the torque converter 4 by a small amount. To understand the present invention, a few basic facts must be taken into consideration. First of all, the input torque of a torque converter is proportional to the square of the input speed of the torque converter, or, in respect to that illustrated in FIGURE 1, to the square of the output speed of the engine, the input shaft of the torque converter being connected to the engine shaft. This is an inherent characteristic of torque converters, as pointed out in the Proceedings of the Institution of Mechanical Engineers, 1957/58, No. 4, page 104 where it is stated that the torque required to drive a rotor containing a constant volume of fluid varies with the square of the speed. As is also known, for example, from the Proceedings of the Automobile Division (The Institution of Mechanical Engineers) 1957/58, No. 4, page 106, in a hydraulic torque converter, the output speed and therewith the driven speed automatically adjusts itself to suit the load without altering the engine controls, i.e., without affecting the input speed. Applying these well-known principles to a locomotive as illustrated in FIGURE 4, if the engineer adjusts the engine to a predetermined speed and the locomotive is decelerated, for example, by an incline, then the velocity of the locomotive decreases; that is, the rotational speed of the wheel sets 9 decreases. Simultaneously therewith, the rotational speed of the axle drives 8, of the axle shafts 7, of the distributor gears 6, of the articulated shafts 5 and finally also the output speed of the output shaft of the hydrodynamic torque converter 4 would decrease. However, the rotational speed of the input shaft 3 of the torque converter 4 would not change as a result thereof. In other words, any change in the rotational speed of the output shaft of a torque converter normally has no influence on the rotational speed of the input shaft. Hence, even though the speed of the train may decrease under the conditions mentioned above as a result of the incline, the rotational speed of the shaft does not change. Since the shaft 3 rotates as before at the rotational speed adjusted at the rotational speed governor 16, the governor 16 neither lowers the rod 15 nor does the decrease in train speed affect the position of the abutment 87.

If the engineer desires to avoid a deceleration of the train velocity, then he merely increases the engine rotational speed, as is usual, by an appropriate adjustment at the governor 16 in order that the engine produces a greater output. If no lack of oxygen exists, the additionally injected fuel quantity is combusted to produce the additional torque.

It is also to be noted that the torque produced by the torque converter varies as a function of the slippage. Hence, with a predetermined setting of the governor 16, maintaining a constant engine rotational speed, a new equilibrium condition will be established, possibly at a different train speed, no adjustment of the abutment 87 being contemplated as long as the engine speed remains the same. Assuming the incline and the train load being such that the maximum torque produced by the engine at maximum rotational speeds is inadequate to pull the train, eventually the train might even stall, though such conditions are normally unlikely to occur in view of the design considerations giving to the pertinent factors. Nevertheless, there is nothing to prevent the input shaft of the torque converter, i.e., the engine shaft to continue to rotate even though the output shaft of the torque converter may be zero.

Since the input torque of a torque converter is, as pointed out above, proportional to the square of the rotational speed of the input member, it is necessary to match the fuel limiting control intended by the present invention to a similar square law function. This is achieved as the pressure of the fluid medium in conduits 22 and 43, space 44 and cylinder 81 is substantially proportional to the square of the engine rotational speed. This produces an appropriate matching of the fuel limitation control to the input torque of a torque converter. One only needs to recall that the centrifugal force acting on the flyweight 35 of the regulator 30 is proportional to the square of the rotational speed of shaft 34 so that the force of the angle levers 36 acting on the collars 37 is proportional to the square of the rotational speed. The force of the pressure medium prevailing in space 44, normally in equilibrium with the force acting on collar 37, opposes the latter force. In a stationary condition, i.e.,

at constant rotational speed, the control slide valve 32 assumes the position illustrated in FIGURE 2 without being displaced axially. This means, the force of the angle levers 36 on the collar 37 is equal the force of the pressure medium in space 44 on the slide valve 32. Consequently, the pressure of the pressure medium in the fluid system 22, 43, 44 and 81 has to be proportional to the square of the rotational speed of the engine.

By changing the tension of the spring 163 by means of the adjusting screw 164, the engine rotational speed can be changed. The higher the adjusted rotational speed, the higher the output of the internal combustion engine. With a diesel locomotive, the engineer can select different rotational speeds depending on the required power output which in turn depends on the weight of the train, on the train velocity, the incline, etc. For example, rotational speeds of 1,000; 1,100; 1,200; 1,300; 1,400 or 1,500 may be selected by the engineer. The fuel-limiting control of the present invention operates at any of these selected rotational speeds. If the engineer, for example, has selected a rotational speed of 1,200, a lack of oxygen occurs when travelling through a long tunnel. As a result thereof, the entire injected fuel can no longer be combusted in the internal combustion engine. This produces a decrease in the engine torque and engine rota tional speed which now drops to, for example, 1,150 r.p.m. The governor 16, however, attempts to re-establish the rotational speed of 1,200 r.p.m. The adjusting rod 15 is readjusted to a new position in which more fuel is injected. Since already the fuel quantity originally injected could not be completely combusted because of lack of oxygen, the additional amount of injected fuel increased as a result of the operation of the governor 16 cannot be combusted. This leads not only to an increased consumption but also entails the danger of coking of the cylinder head and valves. Notwithstanding the additional amount of fuel that would be injected in the absence of the present invention, the engine rotational speed would remain at 1,150 r.p.m. by reason of lack of oxygen. Again, since the input torque of the torque converter is proportional to the square of the rotational speed, no useful purpose can be gained in injecting more fuel than necessary for the particular rotational speed of 1,150 r.p.m. The injection of the excess fuel is prevented by the fuel limitation system of the present invention. The abutment is adjusted, corresponding to the input torque of the torque converter at the prevailing rotational speed of 1,150 r.p.m. in such a manner as to limit the control rack 15 to a position producing only so much fuel as causes the engine to rotate at 1,150 r.p.m., therewith injecting only so much fuel as can actually be combusted.

The same operation also takes place at any other rotational speed which may have been preselected by the engineer with a predetermined adjustment of the adjusting screw 164.

Referring to FIGURE 4, the diagram of this figure illustrates the limitation of the torque of the engine in dependence on the rotational speed. Plotted along the abscissa is the rotational speed n of the engine, the speed 21 being the idling rotational speed and the speed n being the maximum rotational speed permitted for a particular engine. The torque M produced by the engine is plotted along the ordinate, the maximum torque of the engine being indicated by M The curve A represents the square law configuration of the input torque of the hydrodynamic torque converter. The curve B represents the torque produced by the engine as a result of the control system in accordance with the present invention. Assuming the governor is adjusted to idling speed 11 a certain torque is produced by the engine at that point which is a predetermined amount greater than the input torque of the torque converter. If now, for example, the engineer adjusts the governor to maximum torque, the fuel rack 15 would be instantaneously adjusted to a position that would result in injecting instantaneously the amount of fuel corresponding to maximum engine torque. However, the engine speed does not accelerate inst-antaneously but requires a certain length of time for doing so. Since the input torque of the torque converter increases as a square law function of the acceleration of the engine speed, there would be no point in injecting instantaneously an amount of fuel corresponding to maximum engine torque, the abutment 87 only permitting an increase in the amount of injected fuel warranted by the increase in the engine rotational speed. Thus, the curve B -B A indicates the limiting curve determined by the control system of the present invention.

If the temperature of the intake air increases, then under the effect of the temperature-responsive control device 12, the maximum permissive torque is limited, for example, along the curve B -B A With a further increase in the temperature, the torque is so decreased that, for example, the curve B B A is applicable. If the air pressure drops below a predetermined value, then the torque is limited, for example, along the curve B -B A as a result of the influence of the pressure-responsive control device 13.

On the other hand, if the governor 16 is manually adjusted from a higher engine torque to a lower engine torque, obviously the abutment 87 has no influence until the engine rotational speed decreases.

What is claimed is:

1. In combination with an internal combustion engine driving a hydrodynamic torque converter whose input torque is approximately proportional to the square of the rotary speed of the impeller thereof:

means for regulating the rate of fuel supply to the internal combustion engine, said regulating means including a regulating member movable commensurately with the rate of fuel supply to said engine and determining the rate of fuel supply,

movable abutment means constituting a limit means for the maximum fuel supp-1y at any given engine speed and extending into the path of said regulating member for limiting the extent of movement of said member in the direction for increasing the rate of fuel supply to the internal combustion engine,

the position of said abutment means relative to said regulating member being adjustable for varying the extent of the limited movement of said regulating member and therewith the maximum rate of fuel supply allowed by said abutment means,

and speed responsive control means responsive to the speed of said engine and operatively connected to said abutment means for adjusting the position thereof approximately in the same proportionality as the variations of the input torque of the hydrodynamic torque converter in order to vary the maximum rate of fuel supply at approximately said proportionality.

2. The combination according to claim 1, wherein said torque converter drives a vehicle and said engine is a diesel engine, the maximum rate of fuel supply to said engine allowed by said abutment means at each engine speed above idling speed corresponding to a torque produced by said engine which exceeds the input torque of said torque converter at the respective engine speed, the excess torque being substantially equal to the torque required for a predetermined acceleration of the vehicle driven by said torque converter.

3. In combination with an internal combustion engine driving a hydrodynamic torque converter whose input torque is approximately proportional to the square of the rotary speed of the impeller thereof:

means for regulating the rate of fuel supply to the internal combustion engine, said regulating means including a regulating member movable commensurately with the rate of fuel supply to said engine and determining the rate of fuel supply,

abutment means constituting limit means for the maximum fuel supply at any given engine speed and extending into the path of said member for limiting the extent of movement of said regulating member in the direction for increasing the rate of fuel supply to the internal combustion engine,

the position of said abutment means relative to said regulating member being adjustable for varying the extent of movement of said regulating member and therewith the maximum rate of fuel supply allowed by said abutment means,

speed responsive control means responsive to the speed of said engine and operatively connected to said abutment means for adjusting the position thereof approximately in the same proportionality as the variation of the input torque of the hydrodynamic torque converter in order to vary the maximum rate of fuel supply at approximately said proportionality,

and means responsive to the temperature of the intake air admitted to the engine and operatively connected to said abutment means for supplementally adjusting the position thereof for allowing increased fuel supply at decreasing intake air temperature, and vice versa.

4. The combination defined in claim 3, wherein said means responsive to the temperature of the intake air include means for adjusting relatively slightly the position of said abutment means at temperature changes of the intake air below a predetermined temperature and for adjusting relatively extensively the position of said abutment means at equal temperature changes of the intake air above said predetermined temperature.

5. In the combination defined in claim 3, further comprising means responsive to the barometric pressure of the ambient air and operatively connected with said abutment means for supplementally adjusting the position thereof for allowing increased fuel supply at increasing barometric pressure, and vice versa.

6. In combination with an internal combustion engine driving the impeller of a hydrodynamic torque converter whose input torque is approximately proportional to the square of the rotational speed of the impeller:

means for regulating the rate of fuel supply to the internal combustion engine, said regulating means including a regulating member movable commensurately with the rate of fuel supply to said engine and determining the rate of fuel supply,

movable abutment means constituting a limit means for the maximum fuel supply at any given engine speed and extending into the path of said regulating member for limiting the extent of movement of said regulating member in the direction for increasing the rate of fuel supply to the internal combustion engine,

the position of said abutment means relative to said regulating member being adjustable for varying the extent of movement of said regulating member and therewith the maximum rate of fuel supply allowed by said abutment means,

speed responsive control means responsive to the speed of said engine and operatively connected to said abutment means for adjusting the position thereof approximately in the same proportionality as the variations of the input torque of said torque converter in order to vary the maxim-um rate of fuel supply at approximately said proportionality,

and means responsive to the barometric pressure of the ambient air. and operatively connected to said abutment means for supplementally adjusting the position thereof for allowing increased fuel supply at increasing barometric pressure, and vice versa.

7. In combination with an internal combustion engine driving the impeller of a hydrodynamic torque converter whose input torque is approximately proportional to the square of the rotational speed of the impeller:

means for regulating the rate of fuel supply to the in- 12 ternal combustion engine, said regulating means including a regulating member movable commensurately with the rate of fuel supply and determining the rate of fuel supply,

movable abutment means movable relative to said regulating member and extending into the path of said member for limiting the extent of movement of said member in the direction for increasing the rate of fuel supply to the internal combustion engine,

and actuating means for moving said abutment means relative to said member in response to the engine speed at approximately the same proportionality as the variations of said input torque, including:

a cylinder,

a servo-piston movable in said cylinder and operatively connected to said abutment means,

a spring at one side of said servo-piston for urging said servo-piston to move in one direction,

a pressure fluid in said cylinder at the opposite side of said servo-piston for moving the latter against the action of said spring,

a conduit connected to said cylinder for conducting pressure fluid thereinto and releasing pressure fluid therefrom,

a piston valve connected to said conduit for controlling flow of pressure fluid to said cylinder and release of pressure fluid from said cylinder, and a centrifugaltype regulator operatively connected to the internal combustion engine to be driven thereby and to said piston valve for actuating the latter to effect flow of pressure fluid to said cylinder at increasing engine speed and to release pressure fluid from said cylinder at decreasing engine speed and therewith to limit at all times the maximum rate of fuel supply in dependence on the engine speed.

8. The combination defined in claim 7, further comprising manually operable means for moving said piston valve in the direction for releasing pressure fluid from said cylinder.

9. In the combination defined in claim 7, further comprising:

a first pipe connected to said piston valve for conducting pressure fluid to said piston valve,

a second pipe connected to said piston valve for releasing pressure fluid therefrom,

valve means in said first pipe,

and means responsive to the temperature of the intake air admitted to the internal combustion engine and operatively connected to said valve means for opening said valve means upon a decrease of the temperature of the intake air and for closing said valve means upon an increase of the temperature of the intake air.

10. In the combination defined in claim 9, further comprising a two-armed lever interposed between said temperature responsive means and said valve means, said lever having two spaced fulcrums for varying the movement transmission ratio of said lever, means for rendering one fulcrum operative when the intake air temperature is below a predetermined value and for rendering the second fulcrum operative when the intake air temperature is above said predetermined value for opening and closing said valve means to a relatively small extent upon a decrease and increase of the intake air temperature within a temperature range below a predetermined temperature and for opening and closing said valve means to a relatively great extent upon a like decrease and increase of the intake air temperature within a temperature range above said predetermined temperature.

11. In combination with an internal combustion engine driving a hydrodynamic torque converter whose input torque varies approximately as the square of the rotary speed of the impeller thereof:

means for regulating the rate of fuel supply to the internal combustion engine, said regulating means in- .1 g cluding a regulating member movable commensurately with the rate of fuel supply and determining the rate of fuel supply,

movable abutment means movable relative to said regulating member and extending into the path of said regulating member for limiting the extent of movement of said member in the direction for increasing the rate of fuel supply to the internal combustion engine,

and actuating means for moving said abutment means relative to said regulating member in response to the engine speed at approximately the same proportionality as the variations of said input torque, including:

a cylinder,

a servo-piston movable in said cylinder and being operatively connected to said abutment means,

a spring at one side of said servo-piston for unging said servo-piston to move in one direction, a pressure fluid in said cylinder at the opposite side of said servo-piston for moving the latter against the action of said spring,

a speed controlled regulator operatively connected to the internal combustion engine,

a piston valve connected to said speed controlled regulator for movement of said piston valve in one direction upon increasing speed of the engine and in the opposite direction upon decreasing speed of the engine,

a first conduit connected to said cylinder and to said piston valve for conducting pressure fluid from said piston valve to said cylinder upon movement of said piston valve in one direction for moving said abutment means to allow increased fuel supply to the engine,

a second conduit connected to said first conduit and to said piston valve for returning pressure fluid from said first conduit to said piston valve upon movement of said piston valve in the opposite direction for moving said abutment means to cause decreased fuel supply to the internal combustion engine,

a first pipe connected to said piston valve for conducting pressure fluid to said piston valve, said first pipe being connectable by said piston valve to said first conduit,

a second pipe connected to said piston valve for releasing pressure fluid therefrom, said second pipe being connectable by said piston valve to said second conduit,

means responsive to the temperature of the intake air admitted to the internal combustion engine,

valve means interposed in said first pipe, a pressure release conduit connected to and controllable by said valve means for releasing pressure fluid from said first pipe downstream of said Valve means, means operatively interconnecting said valve means and said intake air temperature responsive means for actuating said valve means to permit flow of pressure fluid to said first pipe downstream of said valve means upon a decrease of the intake air temperature and to permit release of pressure fluid from said first pipe downstream of said valve means upon an increase of the intake air temperature,

said means operatively interconnectingsaid temperature responsive means and said valve means including means for altering the position of said valve means relative to said temperature responsive means,

means responsive to the barometric pressure of the ambient air and operatively connected to said means for altering the position of said valve means relative to said temperature responsive means for supp-lementally actuating said valve means to permit release of pressure fluid from said first pipe upon decreasing barometric pressure and to permit flow of pressure fluid to said first pipe downstream of said valve means upon increasing barometric pressure,

12. The combination set forth in claim 11, wherein said means for altering the position of said valve means relative to said temperature responsive means includes a hollow cylinder closed at one end and connected to said temperature responsive means, a piston movable in said hollow cylinder and having an end face facing said closed end of said hollow cylinder, said last-mentioned piston being connected to said valve means, conduit means connected to said hollow cylinder at the closed end thereof, said barometric pressure responsive means including a pilot valve connected to said last-mentioned conduit means and capable of admitting pressure fluid to said hollow cylinder for moving said last-mentioned piston for actuating said valve means to permit release of pressure fluid from said first pipe downstream of said valve means upon decreasing barometric pressure and of releasing pressure fluid from said hollow cylinder for moving said lastmenti-oned piston for actuating said valve means to permit flow of pressure fluid to said first pipe downsteam of said valve means upon rising barometric pressure.

13. The combination according to claim 12, wherein said barometric pressure responsive means includes a member movable in response to the air pressure, a pilot valve connected to said last-mentioned member, a solenoid, said pilot valve having an extension forming an armature extending into said solenoid, and a switch connected to said last-mentioned member for controlling electric current supply to said solenoid, said switch being closed upon decrease of the air pressure below a predetermined pressure and open upon increase of the air pressure above said predetermined pressure.

14. An apparatus for limiting the rate of fuel supply to a diesel engine driving a hydrodynamic torque converter whose input torque is proportional to the square of the rotational speed of the impeller thereof, comprising:

a control rod movable commensurately with the rate of fuel supply to the diesel engine and determining the rate of fuel supply,

a movable abutment extending into the path of said control rod for limiting the extent of movement of said control rod in the direction for increasing the rate of fuel supply to the diesel engine,

said abutment being movable in the path of said control rod relative to the latter for varying the extent of limited movement of said control rod for varying thereby the maximum rate of fuel supply permitted by said abutment,

means for adjusting the position of said abutment approximately at the same proportionality as the variations of said input torque including a centrifugal type speed-controlled regulator connected to the diesel engine to be driven thereby,

a piston valve forming two valves and being connected to said speed-controlled regulator to be actuated thereby, said piston valve being movable from a position for closing the two valves to a position for opening the first of said valves when the engine speed increases above a predetermined value and to a position for opening the second of said valves when the engine speed decreases below a predetermined value,

a source of supply of pressure fluid,

pressure fluid supply conduit means connecting said source to the first of the two valves formed by said piston valve for supplying pressure fluid thereto,

a pressure fluid discharge conduit connected to said first valve for receiving pressure fluid therefrom,

a cylinder connected to said discharge conduit for receiving pressure fluid therefrom,

a piston movable in said cylinder for movement by the action of the pressure fluid,

a spring interposed between said cylinder and said piston for counteracting the action of the pressure fluid, said piston being operatively connected to said abutment for moving the latter in the direction permitting increased fuel supply to the engine when said first valve is opened due to increase of the engine speed above a predetermined speed and the pressure fluid in said cylinder increase, and conversely,

a pressure fluid conduit connecting said discharge conduit and the second of the two valves formed by said piston valve,

and a pressure fluid return pipe connecting said second valve and said source for returning pressure fluid to said source and releasing pressure fluid from said cylinder after closing of said first valve and opening of said second valve due to reduction of the engine speed below a predetermined speed.

References Cited by the Examiner UNITED STATES PATENTS Mallory 123-440 X Reggio 123-14031 Zuhn et a1 123-140 Goetsch et al. 123--140.3 Catford 123-140 

1. IN COMBINATION WITH AN INTERNAL COMBUSTION ENGINE DRIVING A HYDRODYNAMIC TORQUE CONVERTER WHOSE INPUT TORQUE IS APPROXIMATELY PROPORTIONAL TO THE SQUARE OF THE ROTARY SPEED OF THE IMPELLER THEREOF: MEANS FOR REGULATING THE RATE OF FUEL SUPPLY TO THE INTERNAL COMBUSTION ENGINE, SAID REGULATING MEANS INCLUDING A REGULATING MEMBER MOVABLE COMMENSURATELY WITH THE RATE OF FUEL SUPPLY TO SAID ENGINE AND DETERMINING THE RATE OF FUEL SUPPLY, MOVABLE ABUTMENT MEANS CONSTITUTING A LIMIT MEANS FOR THE MAXIMUM FUEL SUPPLY AT ANY GIVEN ENGINE SPEED AND EXTENDING INTO THE PATH OF SAID REGULATING MEMBER FOR LIMITING THE EXTENT OF MOVEMENT OF SAID MEMBER IN THE DIRECTION FOR INCREASING THE RATE OF FUEL SUPPLY TO THE INTERNAL COMBUSTION ENGINE, THE POSITION OF SAID ABUTMENT MEANS RELATIVE TO SAID REGULATING MEMBER BEING ADJUSTABLE FOR VARYING THE 